1. Field of Invention
The present invention relates to an antenna and, in particular, to a dipole antenna.
2. Related Art
The vigorous development of wireless transmission brings various products and technologies applying multi-frequency band transmission, such that many new products have the wireless transmission functions for satisfying customers' demands. The products with multi-frequency functions need to process various signals from the peripheral wireless device, for example, Bluetooth, WiFi, or GPS. With additional functions of WLAN and WiMAX, the signal process is becoming more complex for the products since they need the antenna to receive and transmit the wireless signals that operate at different frequency bands and thus, the antenna that can receive multi-frequency band signal is needed.
The suitable antenna not only matches the appearance of the product and enhances the transmission property, but also further reduces the product cost. The antennas currently used in different products are manufactured in different ways and with different materials.
Conventional dipole antennas usually operate in the band coverage approximately between 2.3 GHz and 2.6 GHz. However, this is not enough for the current wireless communication.
In addition, with reference to FIG. 1, the conventional dipole antenna 1 is to dispose a triangular first radiating part 121 and a triangular second radiating part 122 on a surface of a substrate 11 and to generate the frequency resonance by feeding the signal from a feeding point 13 and a ground point 14, so the antenna can operate. However, this dipole antenna 1 has a smaller operating band coverage that cannot meet the requirement of multi-frequency band on market.
As mentioned above, it is apparent that the conventional dipole antenna does not have sufficient band coverage. Therefore, it is an important subject of the present invention to manufacture a dipole antenna that has a small size and can operate in multi-frequency band.